By Shad Super in Questions —

How Does Googlebot Handle Hashbang (#!) URLs During the Crawling Process?

Summary

Googlebot handles hashbang (#!) URLs by treating them as an indication of AJAX-based content and attempts to crawl the equivalent non-AJAX URLs by transforming them. This enables Googlebot to index dynamic content that uses AJAX for rendering. The hashbang convention has been largely deprecated in favor of pushState and other modern JavaScript APIs that allow for better indexing and crawling.

Understanding Hashbang URLs

Hashbang URLs, containing the #! sequence, were introduced for AJAX applications to provide state information within the URL. These URLs allowed web applications to manage dynamic content without reloading pages. For instance, a URL like http://example.com/#!/page1 would point to a specific state or view within a single-page application.

How Googlebot Handles Hashbang URLs

Fragment Identifier and Crawling

When Googlebot encounters a hashbang URL, it treats the fragment identifier (the part of the URL following the #) as an indicator of AJAX-generated content. Googlebot transforms the hashbang URL into an escaped_fragment= URL, which is then used to crawl and index the content.

For example, the hashbang URL http://example.com/#!/page1 would be transformed into http://example.com/?_escaped_fragment_=page1. This transformation allows Googlebot to request server-rendered versions of the content, ensuring that dynamic content is indexed.

Limitations and Deprecation

The hashbang convention has limitations, particularly regarding user experience and the complexity it introduces. In 2015, Google officially announced the deprecation of the AJAX crawling scheme [Deprecating Our AJAX Crawling Scheme, 2015]. This means that while Googlebot can still crawl these URLs, developers are encouraged to adopt modern web technologies.

Modern Alternatives to Hashbang URLs

Using History API

The HTML5 History API, specifically the pushState and replaceState methods, allows developers to manipulate the browser history and URL without reloading the page. This offers a cleaner URL structure and improved SEO compatibility [History API - MDN, 2023].

Server-Side Rendering (SSR)

Another approach is to implement server-side rendering, which ensures that search engines receive fully-rendered HTML content. This approach enhances both the crawlability and performance of web applications [Rendering on the Web, 2019].

Conclusion

While Googlebot can handle hashbang URLs by transforming them for indexing, the approach is considered outdated. Developers are encouraged to adopt modern techniques like the History API and server-side rendering to enhance SEO and user experience. By moving away from hashbang URLs, web applications can achieve cleaner URLs and more efficient indexing.

References